Forum user thetanktheory built this Glove Mouse to help improve his FPS game skills:

Built from an old laser mouse and some random parts i had lying around. This is a first version and I have quite a few improvements in mind (already working on the next one) but, it functions a lot like I hoped it would. It makes those quick, twitch-reactions in FPS’ much easier. Currently I need to move the buttons over a bit and center the laser a bit more. I plan to add a few more mappable buttons, figure out how to implement a scroll-wheel, lower the laser assembly’s profile, and cover all the functional parts.